Jets?

[FST715]

What's up guys! I'm done modding my kfx700 and now it's time to mod my son's 2007 250ex. But I got a few questions, what are the best jets to work/tune with and where to buy'em? I'd like to stick with the factory brand if they are trouble free.
Also I'd like to see a schematic on the carburator. I took it apart because it had water in it, and it been acting up since then but just sometimes. I think I messed up putting it back together. When I removed the bowl a white piece came off (see pic below, #19) and I didn't see how it was suppose to go and I just guessed it. It runs like is out of gas and runs a little better with full choke pulled.
Anyone?
http://i10.photobucket.com/albums/a108/REDSS01/carburetor.jpg

[ALEXANDERJASON]

THAT WHITE CUP LOOKING PIECE CAN REALLY ONLY GO IN ONE WAY. IT HAS SOME GROOVES ON IT, AND THE CUTOUT AREA SHOULD SIT OVER THE PILOT JET. I DOUBT YOU PUT IT TOGETHER WRONG.

I HAVE AN '07 250EX AS WELL. THE MAIN IS A 95 AND THE PILOT IS A 42. THE PILOT IS LARGER THAN PREVIOUS YEARS, BUT THE CARB IS STILL THE SAME. YOU DON'T NEED TO GO UP ON THE PILOT JET, BUT YOU MAY NEED TO TWEAK YOUR FUEL SCREW SOME. I HAD TO TURN MINE ANOTHER 2 TURNS OUT FROM STOCK. EVERYONE ON HERE WILL TELL YOU THAT IF YOU HAVE TO GO THAT FAR OUT, YOU NEED TO GO UP ON YOUR PILOT JET. IT'S JUST NOT TRUE. I WORKED FOR HONDA FOR A LONG TIME, AND SOME OF THE BEST MECHANICS HAVE TOLD ME THAT YOU CAN GO ABOUT 5 TURNS OUT BEFORE YOU HAVE TO WORRY ABOUT THE SCREW COMING LOOSE.

THE NEEDLE IS NOT ADJUSTABLE ON THE 250EX, AND GOING UP ON THE MAIN WON'T DO MUCH FOR MID-RANGE THROTTLE RESPONSE (WHERE YOU SPEND MOST OF YOUR TIME). I WOULD HIGHLY SUGGEST A DYNOJET JET KIT. THEIR MAIN FOR A STOCK OR SLIGHTLY MODIFIED QUAD IS THE SAME #95, BUT THE NEEDLE HAS A DIFFERENT TAPER, AND IS ADJUSTABLE. IN ADDITION, THE JETS ARE DESIGNED DIFFERENT.

YOU DON'T HAVE TO DO MUCH TO GET MORE FROM THE 250EX. I ADDED 4 OF THE UNI AIRBOX VENTS ON THE TOP OF THE LID. I DON'T LIKE RIDING WITH THE LID OFF AS I THINK YOU ARE JUST ASKING FOR TROUBLE. I GOT ONE OF THE PHOENIX SPARK ARRESTOR ENDCAPS FROM EBAY FOR THE EXHAUST. MORE AIR IN, MORE AIR OUT!! I BACKED THE FUEL SCREW OUT 2 TURNS, AND FINALLY ADDED DYNOJET'S NEEDLE AND MAIN JET.

IT SOUNDS REALLY NICE, AND NOT TOO LOUD. THE PERFORMANCE IS STRONG, AND NOTCEABLY DIFFERENT. ALL FOR ABOUT $120.00

I LIVE NEAR HOUSTON, TX TO GIVE YOU AN IDEA OF RIDING CONDITIONS (SEA LEVEL, HUMID, AND HOT DURING THE SUMMER).

GOOD LUCK WITH THE QUAD AND KEEP US POSTED!!

[FST715]

Well believe or not I did had it wrong. I got rid off the choke, polished the tb/carb, no lid, cut off the stock spark arrestor and modified the muffler as well and changed the main to 135, I know I know is way to big, but that's all I had (it came stock on my KFX700) and I ordered a few jets, 108-120. Even though is running way too rich it feels stronger and quicker than stock.

[m.h.s.c.#527]

im running a 125 main with no lid a an hmf pipe remember leaner is 4 more power and a hotter machine and richer is 4 less power and a cooler machine

[ryanh250ex]

Originally posted by m.h.s.c.#527
im running a 125 main with no lid a an hmf pipe remember leaner is 4 more power and a hotter machine and richer is 4 less power and a cooler machine

true to a point, but get too lean and you'll blow it up :eek2:

I can second Jason's thoughts on going up on the pilot jet. I run NO airbox, full exhaust w/ no quiet core or spark arrestor, etc etc and still run a 38 pilot. I think my fuel screw is out 3.5 turns.

The white cup is a baffle. I dont have mine on.

Edit: FST, check out my Performance FAQ at the top of the page if you need some pointers for jetting your son's 250.

[FST715]

Originally posted by ryanh250ex
Edit: FST, check out my Performance FAQ at the top of the page if you need some pointers for jetting your son's 250.

I got the jets that I ordered and I ended it up putting a 108 main jet, should be close. All I have is the stock filter without the metal insert, no lid, no choke, polished slide and carburator and the stock header with a modified stock can (no spark arrestor or quiet core whatever is that).